Farmpunk... but... uh... wa!
SO MUCH POTENTIAL!
*brain explodes into world crafting gear*
Moonshine seems to be floating in as the end-all. Healing, weapons, etc. Generally what Wizards of the Coast would call "a positive energy weapon.
Thus, one could assume a negative energy existed as well, the weapon of the creepies further mention that the hobos keep away(?).
But what is the opposite of moonshine?!
Water? Fast food (something intimately associated with the city)?
Got it.
Pesticides.

Also, I believe this is so far off the tracks of anything ever pioneered with 3.5 that we need to hand-craft a system to pull it off. I would help out, for sure, if it is agreed that we need to homebrew a system.